Apparatus for grinding of rod-shaped workpieces

ABSTRACT

Grinding or polishing apparatus for rod-shaped metallic workpieces which issue from the rotary head of a shaving machine comprises a driven disk-shaped holder whose hub defines a passage for workpieces which leave the shaving head, an endless grinding or polishing belt which is adjustably mounted on the holder, and an electric motor which drives the belt and is mounted directly on the holder. The tensioning pulley for the belt is adjustable to enable the apparatus to treat workpieces of different diameters as well as to move the belt away from the path of cylindrical leading ends of successive workpieces.

United States Patent Krejan et al.

APPARATUS FOR GRINDING OF ROD- SHAPED WORKPIECES Inventors: FriedhelmKrejan; Ferdinand Beese, both of Mulheim-Ruhr; Hans l-liifner, Essen-West; Franz Riedel, Solingen; Rainer Holzmann, Dinslaken, all of GermanyAssignee: Th. Kieserling 8: Albrecht, Solingen, Germany Filed: July 30,1969 Appl. No.: 846,201

Foreign Application Priority Data 51 May 30, 1972 Pn'mary Examiner-JamesL. Jones, Jr. Attorney-Michael S. Striker [57] ABSTRACT Grinding orpolishing apparatus for rod-shaped metallic workpieces which issue fromthe rotary head of a shaving machine comprises a driven disk-shapedholder whose hub defines a passage for workpieces which leave theshaving head, an endless grinding or polishing belt which is adjustablymounted on the holder, and an electric motor which drives the belt andis mounted directly on the holder. The tensioning pulley for the belt isadjustable to enable the apparatus to treat workpieces of differentdiameters as well as to move the belt away from the path of cylindricalleading ends of successive workpieces.

3 Claims, 4 Drawing Figures Patented May 30, 1972 4 Sheets-Sheet 4INVENTORS: TmzDHzw KQEJAM mmy 552:5

fiuua 2129a RAWEK Ho g W APPARATUS FOR GRINDING OF ROD-SHAPED WORKPIECESBACKGROUND OF THE INVENTION The present invention relates to apparatusfor removing material from external surfaces of elongated metallicworkpieces, particularly from external surfaces of solid cylindrical ortubular mandrels which move lengthwise. Still more particularly, theinvention relates to improvements in grinding and/or polishing apparatuswherein the material removing element is a driven endless belt whichorbits about axially advancing workpieces.

Machines for the production of seamless metallic tubes often employelongated cylindrical mandrels which are withdrawn from freshly rolledor otherwise formed metallic tubes and whose external surfaces must besubjected to at least some treatment prior to repeated use in theproduction of such tubing. As a rule, the external surfaces of mandrelsare treated in shaving machines which remove some of their material.However, the tool or tools of the shaving machine normally leave sometraces (grooves or ridges) and such unevennesses are particularlyundesirable when a mandrel is thereupon used for the production ofthin-walled tubing. It was found that the grooves or ridges cause theformation of cracks. It is therefore customary to subject a freshlyshaved mandrel to a secondary treatment, for example, to the action ofsmoothing tools to reduce the depth or height of grooves or ridges.However, even such secondary treatment of mandrels does not alwaysprevent the formation of cracks in thin-walled seamless tubes.Therefore, manufacturers of seamless tubing presently prefer to subjectmandrels to a shaving and thereupon to a precise grinding and/orpolishing treatment.

Combined grinding and shaving machines are already utilized inconnection with treatment of metallic wire. In such machines, theshaving unit is located ahead of the grinding unit. The latter includesa revolving head which carries several grinding disks which are biasedby springs radially inwardly toward the path of wire. A drawback of suchgrinding units is that a satisfactory surface finish can be achievedonly if the revolving head carries a large number of grinding disks,namely, grinding disks which are disposed lengthwise along the path ofthe advancing workpiece whereby the grinding unit contributessubstantially to an increase in the overall length of the combinedshaving and grinding machine. Reference may be had, for example, to US.Pat. No. 2,394,381. The grinding units of such machines cannot be usedin machines for shaving of mandrels or analogous rod-shaped metallicworkpieces because the machine would have to be provided with separatetransporting means to advance workpieces through the grinding unit.

It is also known to shave mandrels or like workpieces by means of anendless belt which is mounted on a revolving disk and is driven inresponse to rotation of the disk about its axis. A drawback of suchproposal (see German Pat. No. 457,663) is that the speed of the beltcannot be regulated or selected independently of the speed of the disk,that the disk cannot be rotated without driving the belt and that, ofcourse, the belt cannot be driven if the disk is idle. This limits theusefulness of such apparatus.

Certain other conventional proposals are disclosed in German Pat. No.1,087,929 and in German DAS No. 1,181,092.

SUMMARY OF THE INVENTION An object of the invention is to provide anovel and improved grinding and/or polishing apparatus for rod-shapedmetallic workpieces which can be installed in presently known shavingmachines, which is capable of grinding and/or polishing workpieces ofdifferent diameters as well as workpieces with cylindrical or conicalleading ends, and which is simpler, more compact and less prone tomalfunction than presently known apparatus.

Another object of the invention is to provide a grinding and/orpolishing apparatus which need not be provided with its own transportingmeans for workpieces and which is constructed in such a way that it canbe installed in many presently known rod shaving machines withoutnecessitating any appreciable alterations in the design and/or mode ofoperation of such machines.

A further object of the invention is to provide the apparatus with novelmeans for mounting, driving and adjusting its endless material removingbelt.

An additional object of the invention is to provide an apparatus whoseoperation can be controlled by hand or automatically, preferably insynchronism with transport of workpieces therethrough, and whichcontributes very little or not at all to the overall length of a shavingmachine in which the apparatus is put to use.

Still another object of the invention is to provide a grinding and/orpolishing apparatus which can be rapidly converted from treatment ofworkpieces with cylindrical leading ends to treatment of workpieces withdififerently configurated leading ends, or vice versa.

The grinding apparatus of our invention comprises a housing or mainsupport which can be installed in or on the frame of a shaving machine,preferably between the revolving shaving head and the withdrawingmechanism of such machine. It comprises a holder which is rotatablymounted in the support and defines an axially extending passage forfreshly shaved workpieces which move lengthwise under the action of oneor more clamping or gripping devices forming part of the aforementionedwithdrawing mechanism, an endless material removing belt mounted on theholder and arranged to engage the surfaces of moving workpieces, anddrive means for driving the belt, including prime mover means mounteddirectly on and rotating with the holder. Such prime mover meanspreferably comprises an electric motor whose output shaft is directlycoupled to the shaft of the driver pulley for the belt and whichreceives current from an external energy source by way of conductorsmounted in or on the support, preferably by way of a set of slip rings.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved grinding apparatus itself, however, both as to its constructionand its mode of operation, together with additional features andadvantages thereof, will be best understood upon perusal of thefollowing detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side elevationalview of a shaving machine for metallic rod-shaped workpieces whichincludes a grinding apparatus embodying one form of our invention;

FIG. 2 is an enlarged axial sectional view of the grinding apparatusshown in FIG. 1;

FIG. 3 is an end elevational view substantially as seen in the directionof arrow III of FIG. 2; and

FIG. 4 is a similar end elevational view of a slightly modified grindingapparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a shavingmachine for tubular or solid cylindrical metallic workpieces 2. Themachine comprises a frame 1 which accommodates a rotary shaving head 10of known design. The feeding unit which transports workpieces 2 toward,through and beyond the shaving head la in the frame 1 comprises drivenrolls 3. The withdrawing unit which engages and transports shavedworkpieces 2 downstream of the shaving head In comprises grippingmembers or claws 4 which are mounted on a reciprocable slide or carriage5. The latter either slides or rolls (with its wheels) along a base orbed 6 of the frame 1 and is movable back and forth by the piston rod 60of a double-acting hydraulic cylinder, not shown. The heretoforedescribed parts by themselves form no part of the present invention. Theinvention resides mainly in the provision of a grinding and/or polishingapparatus which comprises a main support or housing 7 installed betweenthe shaving head 1a and the carriage 5. The driven endless belt 11 (FIG.2) of the grinding apparatus in the housing 7 treats the shavedworkpieces 2 immediately after they advance beyond the shaving head 1a.

As shown in FIG. 2, the housing 7 accommodates a rotary disk-shapedholder 8 which comprises a hollow extension or hub 80 coaxial with theshaving head la and having a bore whose diameter exceeds the diameter ofshaved workpieces 2'. The holder 8 supports a driver pulley 9 and atensioning pulley 10 for the endless belt 11. The means for rotating theholder 8 about the axis of its hub 8a comprises a driven gear 12 fixedto the hub 8a, a prime mover here shown as a variable speed electricmotor 13 which is mounted externally on the housing 7, and a driver gear13a which is fixed to the output shaft of the motor 13 and mates withthe gear 12. The hub 8a rotates in roller bearings 14 which areinstalled in the housing 7.

The holder 8 further serves to support a second prime mover here shownas a variable speed electric motor 15 which can rotate the driver pulley9 independently of the motor 13, i.e., the speed of the holder 8 can beadjusted and selected independently of the speed of the belt 11. Theoutput shaft 15a of the motor 15 is directly coupled to the shaft 9a ofthe driver pulley 9. The means for connecting the motor 15 in circuitwith a source of electrical energy (not shown) comprises a set of sliprings 16 mounted in the casing 7.

The tensioning pulley 10 is mounted on a shaft 10a which is secured to aplunger 10b received in a cylinder 10c and biased away from the pulley 9by a prestressed helical spring 17. The arrangement is such that thebias of the spring 17 is assisted by centrifugal force when the holder 8is driven by the motor 13. When the belt 11 is used for grinding orpolishing the external surfaces of cylindrical workpieces 2 (namely, ofcylindrical workpieces whose leading ends or tips are also cylindricalshape), the tensioning pulley l0 and the parts Illa-10c, 17 are mountedon a carrier or lever 19 in a manner as shown in FIGS. 2 and 3. Thelever 19 is turnable about the axis of the driver pulley 9 and has anarcuate projection or arm 19:: whose center of curvature is located onthe axis of the pulley 9. The arm 19:: is guided in a bracket 20 whichis affixed to the holder 8 so that the lever 19 can pivot about the axisof the pulley 9. The means for pivoting the lever 19 comprises adouble-acting hydraulic or pneumatic cylinder 22 which is adjustablymounted on the holder 8 and has a piston rod 21 articulately coupled toa median portion of the lever 19. The means for supplying a pressuremedium to and for evacuating pressure medium from the chambers of thedouble-acting cylinder 22 comprises conduits 23, 23a which communicatewith axially parallel bores 24, 24a of the holder 8 (see particularlyFIG. 2), circumferential grooves 25, 25a provided in a stationary sleeve26 which is adjacent to the end of the hub 8a and is affixed to thecasing 7, and preferably solenoidoperated valves (not shown) whichregulate the admission and evacuation of pressure medium from thegrooves 25, 25a. The grooves 25, 25a respectively communicate with thebores 24, 24a in each angular position of the holder 8. Theaforementioned valves can be manipulated by hand or in automaticresponse to lengthwise travel of workpieces 2 toward, through and beyondthe holder 8. The double-acting cylinder 22 is fixed to a projection 27aof a slide 27 which is mounted in ways 27b of the holder 8 and ismovable radially of the holder by a feed screw 28. The parts 27, 28serve as a means for selecting the initial position of the belt 11(shown in FIG. 3 by solid lines) as a function of the diameters ofworkpieces 2'. The purpose of the double-acting cylinder 22 is to movethe belt 11 away from the path of advancing workpieces 2' when thecylindrical leading end 20 of a workpiece approaches the grindingapparatus. Thus, the piston rod 21 of the cylinder 22 can move the belt11 between the solid-line position and the phantom-line position 11 ofFIG. 3. The solid-line position of the belt 11 is selected by the feedscrew 28 and slide 27.

FIG. 2 illustrates an induction coil 29 which forms part of anoscillating circuit and serves to actuate the aforementioned valveswhich control the flow of a pressure medium to and from the chambers ofthe cylinder 22. The inductance of the coil 29 changes when it isapproached by the leading end 2a of a fresh workpiece 2' whereby theoscillating circuit is unbalanced and produces a signal which isamplified and transmitted to the relay means for the solenoid valves toeffect movement of the belt 11 first to the phantom-line position 11'and thereupon to the solid-line position of FIG. 3. In this way, theleading end 2a cannot damage the belt and the latter automaticallyengages the peripheral surface of the workpiece 2' as soon as the frontface of the leading end 2a cannot interfere with return movement of thebelt to the solid-line position. An oscillating circuit which can beused in the grinding apparatus of FIGS. 1 to 3 to serve as a contactlessinitiator for energization and deenergization of solenoids of valveswhich control the flow of pressure medium to and from the chambers ofthe cylinder 22 is described, for example, in German Utility Model No.1,885,761.

FIG. 4 illustrates a portion of a simplified grinding and/or polishingapparatus wherein the lever 19 is not needed because the leading end 2a"of a freshly shaved workpiece is of frustoconical shape. Therefore, theconical surface of the leading end 2a" can properly engage and cannotdamage the belt 11 when the workpiece moves lengthwise and its end 2aenters the grinding station. The tensioning pulley l0 and the cylinder10c are mounted on a bracket or support which is movable along anarcuate guide groove or slot 18 provided therefor in the holder 8. Thebracket 100 can be fixed in any one of a large number of difierentpositions to properly locate the belt 11 with reference to workpieces ofdifferent diameters. When the right-hand stretch of the belt 11 isengaged by the conical surface of a leading end 2a", such stretch isdeflected to assume the phantom-line position 11".

An important advantage of our grinding apparatus is that the prime mover15 for the belt 11 is mounted directly on and shares rotary movements ofthe holder 8. This reduces the number of parts because the prime mover15 can be connected with the energy source in a simple and space-savingmanner, i.e., by conductors in the form of slip rings 16. Anotherimportant advantage of the apparatus is that its housing 7 occupieslittle room so that it can be readily installed in the space between theshaving head 1a and withdrawing mechanism 4, 5, 5a of a conventionalshaving machine. This brings about the additional important advantagethat the apparatus need not be provided with its own work transportingmeans, i.e., the mechanism including the parts 4, 5, 5a can readily movefreshly shaved workpieces lengthwise through the passage defined by thehub 8a and past the station which accommodates the belt 1 1.

The workpieces 2 can constitute the aforediscussed mandrels which mustbe shaved prior to renewed use in a machine for the production ofseamless tubes or the like.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of our contribution to the art.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims We claim:

1. Grinding apparatus, particularly for removing material from externalsurfaces of freshly shaped metallic rod-shaped workpieces which movelengthwise, comprising a support; a holder rotatably mounted on saidsupport and defining a passage for moving workpieces; an endlessmaterial removing belt mounted on said holder and arranged to engage thesurfaces of moving workpieces; and drive means for driving said belt andcomprising prime mover means mounted on and sharing rotary movement ofsaid holder, a driver pulley operatively connected with said prime movermeans and rotatably means for pivoting said lever comprisesdouble-acting fluid operated cylinder means.

3. Grinding apparatus as defined in claim 2, further comprising meansfor adjustably mounting said cylinder means on said holder.

1. Grinding apparatus, particularly for removing material from externalsurfaces of freshly shaped metallic rod-shaped workpieces which movelengthwise, comprising a support; a holder rotatably mounted on saidsupport and defining a passage for moving workpieces; an endlessmaterial removing belt mounted on said holder and arranged to engage thesurfaces of moving workpieces; and drive means for driving said belt andcomprising prime mover means mounted on and sharing rotary movement ofsaid holder, a driver pulley operatively connected with said prime movermeans and rotatably mounted on said holder, a tensioning pulley remotefrom said driver pulley, said belt being trained over said pulleys, andmounting means adjustably mounting said tensioning pulley on said holderand comprising a lever pivotable with reference to said holder about theaxis of said driver pulley and means for pivoting said lever withreference to said holder.
 2. Grinding apparatus as defined in claim 1,wherein the means for pivoting said lever comprises double-acting fluidoperated cylinder means.
 3. Grinding apparatus as defined in claim 2,further comprising means for adjustably mounting said cylinder means onsaid holder.